Boxwood Butchery

Greetings! Readers of my blog have probably noticed that I have many, many boxwood shrubs -- several hundred -- in my various garden areas. The most prominent boxwood planting is my Herb Garden, shown above in a photo taken three years ago. (This is one of my favorite pictures of my garden, because it shows my white picket fence, the formal Herb Garden, and the Iowa farm scenery beyond -- I feel the photo really captures the feeling of my gardens and their setting.)

The Herb Garden was the first garden area I made when we moved out here in 2008. I had wanted to make a formal garden area for years and had been planning the type of general layout I wanted even before we moved here. We had some grading work done in other parts of our property, to make the retaining wall for our garage and to smooth some lawn areas, so I had the guy with the bulldozer level up this area a bit too when he was out here.

Here's a photo of our house and property taken in fall 2007, before we bought the place. Our garage now stands where the trees at left stood, our driveway area is much larger, and we tore down the small leaning shed. And to the right of the house, the ground sloped down away from the house -- I had that area leveled up so I could make my formal Herb Garden there.

Here's the freshly laid-out Herb Garden, the following summer in 2008. The area is quite a bit more level than it was in the last photo, and I outlined gravel paths with about 200 'Green Velvet' boxwood seedlings that I bought from a nursery in Alabama.

The Problem

But there was a big problem with my boxwood hedges in my Herb Garden: I planted the boxwood seedlings too close together. Each of the beds is 4.75 feet wide and 11 feet long, and I planted the boxwoods less than a foot-and-a-half apart, not realizing that the tiny seedlings had a mature size of three feet wide.

This didn't get to be a problem for some time, because boxwood takes years to grow to mature size. 

Here's a picture from 2014: Six years after planting, the boxwoods were finally growing together nicely, and I was able to trim them into continuous hedges.

By 2018, the boxwood hedges had gotten quite a bit larger (you can see how much taller the hedges were compared to the solar lights at the entrance, from the previous photo). I needed to remove a lot of the growth each year, in order for there to be room in the beds for herbs to receive any light.

The boxwoods continued to grow. I trimmed them every year, but found myself needing to trim more off of them each time, so that there was room to grow herbs in the beds. The design still looked good, though.

But spring of 2019 was exceptionally wet. The previous autumn (Fall 2018) was unusually wet, plus a lot of snow melted off in winter, and then it just wouldn't stop raining in spring 2019. Our basement actually flooded with an inch or two of water that spring (our house is on the top of a hill and our basement is tiled for drainage, so this was very unusual).

I waited until July of that year when things were finally dry to trim the boxwoods -- it's a bad idea to cut them when they're wet, because it makes them more susceptible to diseases. But apparently that precaution wasn't enough to prevent a problem.

This photo, taken in May 2020, shows that there is a problem.

I didn't notice the problem until nearly a year later, last May -- although I had vaguely noted that the boxwoods hadn't grown as much during 2019 as they usually do. Looking back at photos from Fall 2019, it's obvious now that they weren't growing well.

But by May 2020, the problem was all too visible: there were dead branches and whole dead areas on many of the boxwood shrubs.

Boxwood Blight?

For years now, I have been terrified that the dreaded Boxwood Blight will infest my gardens like it has in England and, to a lesser degree, in the eastern and southern US. There is no effective treatment for it, and it would necessitate the removal of my hundreds of boxwoods -- including this entire Herb Garden area. (When we returned from our trip to England in 2019, I scrubbed the bottoms of our shoes with disinfectant before getting on the return plane. Don't laugh: we visited a garden the day before our flight home in which the boxwoods looked horribly diseased.)

When I saw this damage, my heart nearly stopped. I immediately contacted our state Extension's Plant & Insect Diagnostic Clinic last May, but they were closed for lab work due to the coronavirus -- although people were answering emails.

So I did some more research online myself, and I realized from the symptoms that it's likely not Boxwood Blight (a fungal disease caused by Calonectria pseudonaviculata), which causes the boxwood leaves to fall off the plant.

Instead, it's likely Volutella blight (caused by the fungus Volutella buxi / Pseudonectria buxi), in which the leaves die but remain on the plant. The Extension person who emailed me agreed from the photos I sent that this was likely the case (although she wasn't able to do a lab confirmation).

Here's what the inside of that hedge with the dead streak looks like: interior dieback, but with the dead leaves retained on the plant.

Plus, I closely looked at some leaf samples, and they matched the descriptions of the symptoms described in the linked article from the Tennessee State Extension:

There are some "black streaks on petioles" (where the leaves attach to the stems), but not streaking
all the way up the stems, like in Boxwood Blight.

And here are the "salmon pink colored fruiting bodies (sporodochia)" mentioned in the article.

So the (very) good news is that my Herb Garden boxwoods are not the first documented case of Boxwood Blight in the state of Iowa. (Although it's still probably only a matter of time until it arrives, as it's been found in Illinois and Missouri, our neighboring states -- but not today.)

The outlook seems pretty grim, as many of the states around Iowa already have spotted boxwood blight there. Only a matter of time....

But the bad news is that I still have a blight problem, albeit one that that I might, with time, be able to mitigate and, with luck, be able to save my boxwood shrubs.

Boxwood Butchery

Two weeks ago I (and my 15-year-old son) began my radical project: to remove every other boxwood shrub in my Herb Garden and trim out the dead branches, opening up the remaining parts of the shrubs to more air circulation. With time, the remaining boxwoods might fill in and make a (looser) hedge again. I'll also treat the boxwoods with a copper-based fungicide over the next few years.

Here are a few photos, to revel in the carnage:

Like a crenellated castle wall.

Butchered.

After sawing off every other shrub, Step 2 is to cut out the interior dead branches and knock out all of the dead, diseased leaves trapped inside each shrub. This is pretty time-consuming, and I had to stop when it started raining two weeks ago -- but as soon as things dry out I'll resume this work.

And the lower limbs of each shrub that were lying along the ground need to be trimmed off, so air will be able to circulate under the shrubs. And note all those dead, diseased leaves from years of trimmings littering the ground. Those were hidden by the lowest limbs before.

There are literally heaps of boxwood leaves on the gravel paths. The leaves are so tiny it's difficult to rake them up effectively. But years of leaf detritus -- especially the diseased leaves covered in spores -- must be removed and burned, or disposed of in the garbage.

This arrived today. I should have bought one of these years ago to suck up the leaves after trimming the boxwoods -- I trim them every May or June. This kind of leaf hygiene might have helped prevent the blight in the first place, and I'm planning to use it from now on each year to keep the paths and the interior of the shrubs tidy.

Here's a view from an upstairs window, showing the butchery in all its gruesomeness. My Herb Garden hedges are going to look like a mouth with every other tooth missing for probably the next three to five years. Oh well. 

I had planned to open my gardens this year, but it might be a few more years until I do that now. But I really do hope that eventually the boxwoods will look good again -- and be healthier too. I'm a patient gardener and the years will pass before I know it. With some luck, this, my first garden area, will eventually be rejuvenated.

I hope your own gardens are beautifully blight-free, and that you are enjoying warm spring days outdoors. And thanks for reading this long and somewhat cheerless (but still hope-filled) post. Best Regards, -Beth